NSXMLParser silently drops internal entities

Number:rdar://22358140 Date Originated:20-Aug-2015 01:16 AM
Status:Open Resolved:
Product:iOS Product Version:8.4
Classification:Serious Bug Reproducible:Always
Given an XML file with internal entity definitions, NSXMLParser ignores entity references, that is it never calls parser:foundCharacters: with the entity reference expansion.

For example, given the file:

<?xml version="1.0" standalone="yes" ?>
<!DOCTYPE foo [
  <!ENTITY bar "Johnnie Fox's">
  Entity expansion test begin &bar; end.

The parser will make the following delegate calls (ellipses indicate places where  parameters have been removed for clarity):

-[… parserDidStartDocument:…]
-[… foundInternalEntityDeclarationWithName:@"bar" value:@"Johnnie Fox's"]
-[… didStartElement:@"foo" namespaceURI:nil qualifiedName:nil attributes:{
-[… foundCharacters:@" Entity expansion test begin "]
-[… foundCharacters:@" end. "]
-[… didEndElement:@"foo" namespaceURI:nil qualifiedName:nil]
-[… parserDidEndDocument:…]

The parser exits successfully and no error is reported.

Steps to Reproduce:
Run any XML that contains an internal entity reference (such as the example above) through NSXMLParser and observe the delegate calls.

Alternatively, run the test testInternalEntityReference in the attached Xcode workspace and examine the NSLog and/or notice the test fails.

Expected Results:
Given that NSXMLParser has no delegate method that is called when an internal entity reference is encountered, it is reasonable to expect that the expanded entity would be passed to the delegate in a call to parser:foundCharacter.

Using the example above and ignoring some irrelevant calls this would look like this:
-[… foundCharacters:@" Entity expansion test begin "]
-[… foundCharacters:@"Johnnie Fox's"]
-[… foundCharacters:@" end. "]

Actual Results:
See summary above

I could not find a version of NSXMLParser where this worked.
Both libxml2 and expat handle this correctly.

Provide additional information, such as references to related problems, workarounds and relevant attachments.


Still open after all these years.

This is now FB22358140

By iosdeveloperzone at June 16, 2019, 5:01 a.m. (reply...)

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